Commercial condensing Boiler domestic property

[StClaires]

We have been advised to replace two woefully inefficient older Ideal boilers (there are not linked and have a combined 60 kw max output if I remember correctly) with one small commercial boiler - a Worcester GB162 80kw boiler. We require around 72kw ish.

A bit of background- It is a large, older detached house ( long and narrow over 3 floors) which we have been doing up for over a decade. It will ultimately house 3 teenagers, 2 adults and reqular /extended visits from elderly parents. There is loft insulation and some cavity wall insulation. We are addressing where various extensions have been added without insulation. We use some rooms all the time, some like bedrooms at certain times of day and others only occaisionally.

We currently operate 4 zones on our existing system.
The heating being split into 3 zones the hot water a zone in its own right. The radiators have trvs but we do not have any room thermostats.

We want to try to maximise efficiency on a room level if possible. My questions are:

1. How do Worcester rank in terms of efficiency and longevity? Which other manufacturers should we be considering.

2. Is there any way/benefit of having room level heating control with out having a wall mounted room thermostat in each room.

3. Are weather compensators necessary/useful? Is there a difference between those that use the external temperature as opposed to internal only. (I read, somewhere on here, what I interpreted as someone only using the internal temperature).

4. Should we be going for a different type of system altogether?

5. Is there anything I haven't mentioned here that we should be considering /aware of.


Many thanks in advance.


StClaires

 

[ALEC1]

Have you done a heat loss calculation..you may well be surprised..what is the floor area..one of my projects is 760m2 and needs 50kws.. ok I am in London...a bit warmer...

Zoning does have its uses but pretty point less in most houses in the UK..

 

[StClaires]

Have you done a heat loss calculation..you may well be surprised..what is the floor area..one of my projects is 760m2 and needs 50kws.. ok I am in London...a bit warmer...

Zoning does have its uses but pretty point less in most houses in the UK..

Calcuations were done by British Gas Engineers domestic who refererred us to commercial part. Then 2nd one done by commercial british gas engineer.

 

[ALEC1]

Some European boiler manufacturers use an approach accross the board for bigger properties...they use the principle of mixed and unmixed circuits...the unmixed being hotter than the mixed which is achieved by the use of compensated mixing valves...The other big difference is that they do not seek to turn boilers off in winter, they seek to vary the temperatures of the circuits using temperature profiling...that is one heating time window and set back temperatures...so the system only shuts down when it is above those temperatures... the rest of the time it seeks to give you a stable temperature indoors...

Its probably best to think about the circuits...is it all radiators? What is the idea of maximising efficiency at room level? an 80 kw boiler is unlikely to have a minimum modulation below 16kws....thats the minimum load you want to entertain in the regularly habited rooms...do a calculation around that.

then divide up the house into manageable circuits...with common heat emitters...ufh in wood, ufh in screed with stone coverings ufh in screed with wood coverings..


so yes weather comp is the way to go...bosch, viessmann atag will all have similar approaches and products...

80kw takes you to a commercial ticket so expect it to be expensive...70kw keeps it in the domestic range...and will be more competitive..

 

[D_Hailsham]

Calculations were done by British Gas Engineers domestic who referred us to commercial part. Then 2nd one done by commercial british gas engineer.

It might be a good idea to do your own using the Whole House Boiler Size Calculator

If your house is a complicated shape, divide it into joined-together sections.

 

[Biggles..]

The GB162 is a good boiler, you won't go far wrong.
Trouble will be that this boiler is classed commercial even the ones under 70kw so your average domestic installer can't fit it. Most will try and get you to waste your money on two domestic sized ones just so they can get the job.

Getting the right system is just as important as the the choice of boiler, Alec loves Compensation controls but that doesn't mean it suits all buildings an your budget. Mixed and un mixed is all well and good on paper but add that to the over inflated cost of the commercial boiler and your budget will spiral out of control as will using manufacturers own controls.

The cascade controller or boiler management control for the gb162 is ridiculous money.

Other option would be Vaillant Eco Tec 65, or broag quinta 65.[/quote]